Roll glslang forward to 02c70ad10e1f9dc88ae4ee509f26fe5f9fb31843

Roll glslang forward to 02c70ad10e1f9dc88ae4ee509f26fe5f9fb31843

This includes fixes for newer compilers, including the official toolchain for the upcoming Android release.

For example, modern clang currently complains:

In file included from
external/deqp-deps/glslang/OGLCompilersDLL/InitializeDll.cpp:42:
external/deqp-deps/glslang/OGLCompilersDLL/../glslang/Include/PoolAlloc.h:307:54:
error: 'operator=' is a private member of 'glslang::TPoolAllocator'
    void setAllocator(TPoolAllocator* a) { allocator = *a; }
                                               ~~~~~~~~~ ^

Affects: dEQP-VK.*
Components: Vulkan
VK-GL-CTS Issue: 2344

Change-Id: I85e94fea0621c3b72e6f30e7e68377c41449be99